Lubricating oil



Patented June 30, 1942 trap sfra'ras FATE @FFHCE mesne assignments, to

Botany-Vacuum i! Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application August 26, 1938,

a Serial No. 226,983

1 illaim.

This invention relates to lubricating oils. and more particularly to improved lubricating oils of high film strength, high resistance to oxidation, and markedly reduced formation of corrosive products during use.

This is a continuation in part of my co-pending application, Serial No. 70163, filed- March 21, 1936.

Present-day mechanical devices require lubricating oils of high film strength, of high .oiliness characteristics, and of low tendency to oxidize during use. It has been found that the presentday hydrocarbon lubricants of the very highest quality are deficient in these very important characteristics. These three properties are of vital importance under conditions of thin film lubrication where the lubricant has been squeezed from between the friction surfaces because of high pressure, slow speeds, and other causes. In modern engines, large surfaces of oil are exposed to the action of atmospheric oxygen, promoting rapid oxidation. It is readily seen that the viscosity or the body of the lubricant plays no part in thin film lubrication and that the remaining film of oil must have a very high film strength and be of high oiliness value to prevent rupture of the film of the lubricant, which would cause seizure. The oil film must tend to keep the coefilcient of friction as low as possible. The 011 must resist oxidation when these thin films are heated in the presence of atmospheric oxygen as they are in use.

Mechanical devices are being designed for higher pressure operation, and the film-strength of the best quality straight hydrocarbon lubricant has been found to be too low for satisfactory service. It will be obvious that an invention which provides a means of improving the film strength of these lubricants is of great importance to the art of lubricant manufacture and to the designer and fabricator of mechanical devices.

Substantially all machines operate in part or ticularly corrosive to bearing metals such as cadmium-silver, copper-lead, and the like.

In starting idle mechanical equipment which is lubricated from a sump by pumping or circulating the lubricant, there is always a short period of time in which the rubbing surfaces must operate under conditions of dry friction if ordinary hydrocarbon lubricants are used. With dry friction, the wear on friction surfaces is extreme; and during cold weather when the lubricant is sluggish or during periods when the lubricating system is not functioning properly for one reason or another, rubbing surfaces may not only suffer considerable wear but may be damaged to the point where they must be replaced. The product of this invention has a very important property of reacting with the metal surfaces, penetrating or adsorbing on the metal surfaces, and leaving a film of lubricant with high oiliness character, which remains on the metal surface irrespective of the length of time the machine hasv been idle.

This high oiliness film gives very even and smooth operation, which may be easily discerned by the experienced operator or lubricating engineer.

When the hydrocarbon lubricants are diluted with unburned fuel or with other light hydrocarbons, the small degree of oiliness of the original hydrocarbon lubricant is greatly decreased. It has been found that theaddition of the products of this invention to hydrocarbon lubricants more than compensates for the loss in oiliness and load-carrying ability from dilution.

It is well known that, in order to obtain lubricants which are preeminently satisfactory from the standpoint of oxidation in use,'it is necessary to refine the oil thoroughly and then to add an inhibitor of oxidation. The thorough refining part of the oil and leave only the most stable at times totally under conditions of boundary ially deleterious under conditions of thin film lubrication. The sludge is not a lubricant in any portion. Such drastic refining is necessary in order to obtain stability with respect to sludge formation, but the oil is then subject to easy oxidation to form soluble acids and other corrosive materials. This can be prevented by the addition to the refined oil of small amounts of materials which either prevent the formation of these corrosive products or by some action render them inert. Furthermore, such well-refined oils are susceptible to the formation during use of lacquer-like materials which tend to stick rings. This results in blow-by and hence loss of power, failure of lubrication, scratching, scoring, oversense of the word, and the soluble' acid is parheating, and eventually replacement of.parts.

It is practically lmpossible'to refine a lubricant in such a manner as to avoid all three ofthese diiliculties, namely, sludge, soluble corrosive products, and lacquer. It is considerably more advantageous to add the materials of this invention and avoid these difllcultles by this method.

Certain compounds are adsorbed or absorbed by metals forming tenacious films at the surface of metals which are able to stand high pressures. X-ray diffraction methods have shown that compounds containing highly polar molecules, that is, molecules of unsymmetrical electrical character containing an atom or group of atoms exhibiting a secondary or residual valence, tend to produce regimentation of the molecules of hydrocarbon oil when added thereto. A metal immersed in a strongly polar compound will show a film of the compound in which there is a regimentation of molecules oriented with respect to the surface of the metal by which they are adsorbed or absorbed. A

Many of these additive materials are effective when added to poorly refined or even wholly unrefined lubricants. The addends may thus be substituted in whole or in part for the usual refining processes.

In the prior art of applying these principles to the manufacture of lubricants, many diverse types of materials have been suggested to be added to obtain improvement in various characteris'tics. It has been found that the addition of various compounds frequently improves film strength, oxidation resistance, noncorrosiveness.

vide film strength improving addition agents suitable for use in lubricants and especially in crankcase lubricants.

Other and further objects of this invention will appear in the course of the following descrip tion.

In general, this invention contemplates an oil of lubricating viscosity having added thereto a small amount of an organo-metallic salt. The organo-metallic salt may be an organo-metallic salt of an organic,-inorganic or organo-metalllc acid. Organic or inorganic salts of organo-metallic acids or organo-metallic substituted acids may be used. The organic parts of these molecules may be radicals of the aliphatic, carbocyclic, or heterocyclic series. The metallic element may be any one of a number of which the following are representative. For convenience these are listed in accordance with their occurrence in the Periodic Table.

Group II:

Beryllium Magnesium Zinc Cadmium Mercury Group III:

Aluminum Thallium Group IV:

Germanium Tin Lead absence Group V:

Arsenic Bismuth Antimony Group VI:

Tellurium Selenium The compound may contain in the organic rad-- ical or attached to the metal an additional element or combination of elements including the halogens, phosphorus, sulfur, nitrogen or oxygen.

The organo-metallic salts of this invention have a dual action in a lubricant. One action involves increased load-carrying ability and/or oiliness, while another action is directed to the stability of the lubricant. For load-carrying capacity, quantities ranging from 0.1 per cent to about 10 per cent may be added. As an anticorrosive agent and/or an anti-sludging agent, much smaller amounts may be required ranging from approximately 0.001 to 0.1 per cent. The action of the organo-metallic salts is specific but difllcult to understand. These compounds may be added to any type of hydrocarbon lubricants but show an unusual value in highly refined and solvent treated lubricants. By oil having lubricating viscosity in the appended claim, it is meant to include the so-called mineral oilsv and various hydrogenated, polymerized and otherwise synthetically treated oils such as voltolized oils, aluminum chloride treated oils, and the like. Furthermore the lubricating oil may consist in whole or in part of shale oil, animal or vegetable oils such as castor oil, lard oil, corn oil, cottonseed oil, and the like. y

In practice, it is better to employ compounds whose boiling point is above 225.F. in order that the addition compound will not be evaporated or distilled in use. The selection of a particular compound or compounds to be used as an addition agent to the hydrocarbon or other oil is to be made considering the physical and chemical properties of the various compounds and the use to which the blend is put. Thus, if water is likely to be present during use, a salt or combination of salts is selected which is not aifected by water. If a particular added compound proves too volatile for its application, a higher boiling material should be used and the more volatile compound used for blending in an.oil intended for duty at lower temperatures. In

' general, for automotive crankcase lubricants, it

is preferred to use compounds having vapor pressures of less than atmospheric at 250 F.

The following compounds may be used in accordance with this invention. All and each of these are to be considered as examples of this invention when blended in an oil of lubricating viscosity. 7 I. Organo-metallic salts of inorganic acids A. Salts of acids of nitrogen l. Salts of nitrous acid Triamyltin nitrite (C5H11)3SI1NO Tribenzyltin nitrite (CsHsCHz) :xSnNOz Tripyridyl germanium nitrite (C5H4N) aGeNOz Trithienyltin nitrite (C4H3S) sSnNOz Furfurylmercuric nitrite (C4H30) HgNOs Di-isoamylaluminum nitrite (C5H11) 2A1NO2 Tribenzyltin p-tert.-amylphenylarsenite CH11C6H4ASO2[SI1(CH2C6H5) 312 Tribenzyltin dipropylarsenate (Cal-I7) 2ASO2SI1(CH2C6H5) 3 Di-omegach1oroamylthallium p-tolylstannonate CH3C6H4SI102T1(C5H1OC1) 2 p-tert.-Amylphenylzinc p-tert.-amylphenylarsenite C5H11C6H4ASO2(ZnCsH4C5I-Iu) 2 p-Aminophenylbismuth dipropylarsenate (CsI-Ir) 2ASO212BiCeH4NH2 Allylselenium laurylstannonate C12H25SnO2SeCsHs Mercaptophenylaluminum p-tert.-amylphenylarsenite C5Hl1C6H4ASO2A1C6H4sH n-Butylberyllium laurylstannonate C12H25SnO2BeC4H9 I Tribenzyltin ethyl-p.-tert.-amylphenylarsenite C5H1lC6H4ASO2 C2H5) Sn CHzCeI-Is) 3 D. Salts of organo -metallic substituted acids Diamylthallium diacetoxymercuri 5 nitrosalicylate (ChsCOzHg) 2C6H(OH) (NO2)CO2T1 (CsHn) 2 Di-(tribenzyltin) mercuri-bis-anthranilate Hg [CsH3 (NHz) CO2Sn(CI-I2CsI-I5) 312 'Iribenzyltin o-chloromercuribenzoate C1HgCsH4CO2SI1 CH2CeH5H Tribenzyltin o-sulfidomercuribenzoate S [Hg.CeI-I4CO2SIl (CHzCeHs) 312 Tribenzyltin beta-mercury-bis-propionate Hg[CH2CH2CO2Sn(CH2CsI-I5) 312 Tribenzyltin alpha-tribenzyltinstearate C17H34 [Sn (CHzCsHs) 3 COzSn (CHzCsHs) 3 Tribenzyltin alpha-diethylthalliumlaurate C11H22 [T1(C2H5) 2]CO2S11(CH2C6H5) 3 Tribenzyltin p-n-butylberylliumbenzoate C4H9BC6H4CO2SI1 CH2C6H5 a Tribenzyltin omega-chloroamylarsenicdibenzoate ClCsHlOAS[C6H4CO2SI1(CH2C6H5)312 Tribenzyltin allylseleniumbenzoate C3H5S6C6H4CO2SI1 CH2C6H5) 3 Aluminum diacetoxymercuri-5-nitrosalicylate [(CHsCOzHg) 2C6H(OH) (N02) CO2 ]3AI Calcium beta-mercury-bis-propionate Hg (CH2CH2CO2) 2C8. Sodium alpha-tribenzyltinstearate CHI-I34 [Sn (CHzCeHs) 3 CO2N2. Ammonium alpha-tribenzyltinstearate C17H34 [Sn CHzCsHs) 3 CO2NH4 Tetramethylammonium alpha-tribenzyltinstearate C1'1Ifi4 [Sn (CHzCsHs) 31CO2N (CH3) 4 Triamylammonium alpha-tribenzyltinstearate C1'1H34[SI1(CH2C5H5) 3] COzNH (Cal-I11) 3 Diethylammonium alpha-tribenzyltinstearate C17H34ESI1 (CH2C6H5) 3] CO2NH2 (C2H5) 2 Phenylammonium alpha-tribenzyltinstearate C17H34 [Sn (CHzCeHs) s] COzNHsCsHs Tribenzyltin tribenzyltinsuccinate Any of these compounds or other members of the classes represented may be used within the scope of my invention.

The organo-metallic salts have varying degrees of solubility in hydrocarbon and other oils. l In some cases it is necessary to use a solvent forthe compound or to form colloidal suspensions of the compound in oil. While some of these compounds have only limited solubility in hydrocarbon oils, it is to be remembered that because of their great eificiency extremely small amounts are often efiective. Thus I may use as little as 0.001 per cent of some of these compounds, and it will be seen that a fairly insoluble material may dissolve to a sufiicient extent to be satisfactory for my purpose. In general, more than 0.001 per cent of my addition agents are used, and I may add one, two, or even five per cent or more.

Furthermore, it is well known that different types of oils have difierent capabilities of dissolving a given material. For some purposes therefore, I prefer parafiinic, for other purposes, asphaltic, and for still other purposes, naphthenic or mixed base lubricants. Another method of obtaining a satisfactory mixture of addition agent with the hydrocarbon oil is the use of a mutual solvent to bring the addend into solution. Alternatively, peptizing agents may be added to maintain the organo-metallic salt in permanent suspension.

Many of the more difficult soluble materials are rendered more soluble by the introduction of alkyl groups, particularly those containing four or more carbon atoms. The isoamyl, octyl,

lauryl, and octadecyl radicals and radicals from in hydrocarbon lubricating oils but tri (cetyl- I phenyltin) phosphate is much more soluble.

It will be obvious from these considerations that all the organo-metallic salts are not equivav lent and that some. are more suitable than others in special cases. Of the examples listed above, for example, the organo-metallic sulfides are likely to be difiicultly soluble in petroleum hydrocarbons and fatty oils. Hence, of these, I prefer the purely aliphatic sulfides such as trilauryltin sulfide or triamyltin sulfide. If it is particularly desired, however, to use an aromatic organometallic sulfide it may best be accomplished by using a compound in which there are at least as many aliphatio'carbon atoms as there are aromatic carbon atoms, or more. Thus I prefer to use triquinolyltin trilauryltin sulfide or 2-ethylhexylphenylzinc sulfide.

In the case of the organo-metallic salts of organic acids, I prefer to use salts of acids having boiling points over C. The salts of the unsubstiuted aliphatic acids such as acetic, are less likely to be suificiently soluble than the trichloroacetates, butyrates, stearates and the like. An exception here, howeveryare the salts of carbonic acid which may be considered an inorganic acid.

It is sometimes advantageous to combine more than one of these compounds in a blend to obtain particular properties. I accomplish this by mixing two or more of these compounds together and. blending the mixture with the hydrocarbon oil or byblending one in the hydrocarbon oil, blending the second into this mixture, and so on until the composition is complete.

The various organo-metallic salts usually improve both the film strength and oxidation characteristics of the hydrocarbon oil. For example, the sludging tendencies may be decreased by as little as 0.001 per cent of my organo-metallic salts compounds. The oxidation characteristics of lubricants are very important, and these are markedly improved by our compounds. The

ability to reduce friction is another feature conphorus containing inhibitors, in addtion to my organo-metallic salts. Furthermore, various other metallic compounds may be added to the blend without interfering with the action of my ingredients. Indeed, in some cases it is advantageous to combine with my organo-metallic salts in a hydrocarbon oil blend such materials as calcium dichlorstearate, chromium oleate, aluminum stearate, and other metallic soaps. Various halogenated oxygen bearing ring or allphatic compounds may be added.

My addends are admirably adapted for use in lubricating oils of all types including those designed for use in automotive crankcases, Diesel oils, and any other oils of lubricating viscosity. Furthermore, my addends are advantageously blended in gasoline and other petroleum fuels either directly or after being blended first in a lubricating oil and then added to the fuel. Soapthickened mineral oils of all types ranging from those showing only a slight increase in viscosity over that of the mineral oil alone to the semisolid and solid greases containing fifty per cent or more of soap are amenable to treatment according to my invention. In making these greases, the usual soaps such as sodium stearate, aluminum stearate, calcium soaps of beta fat, and the like'may be used to form the large part of the necessary soap. Various other thickening ingredients or materials for other purposes may be added. These include yarn, hair, graphite, glycerol, water, lamp black, mica, zinc, dust, litharge and the like.

Some of these organo-metallic salts are more suitable than others for some purposes. Thus iron and lead compounds, in general, are found to be accelerators of oxidation in crankcase lubricants. One the other hand, these same lead compounds, for example, are quite desirable in the manufacture of mild and violent types of hypoid lubricants. Here the value of the extreme pressure characteristics far overshadows the oxidation accelerating ability.

The following examples of blends of my addition agents are given as illustrations and not as limitations:

Example 1 Per cent Mid-Continent parafiin base SAE 30 99.0 Tribenzyltin phosphite 1.0

Example 2 Per cent California naphthenic base SAE 30 98.7

omega Chloroamyl diethyltin monothiophosphate 1.3

product 0.50 Triamylammonium alpha tribenzyltinstearate 0.05

Example 4 Per cent Paraffin base bright stock 58.0 Paraffln base neutral oil 40.0 Sulfurized methyl esters of corn oil fatty acids 0.1 Tribenzyltin stearoylsalicylate 0.2 Calcium dichlorostearate 1.3 Diphenyl-chlorwax condensation product 0.4

Example 5 Per cent Mid-Continent paraffin base SAE 20 98.0 Tribenzyltin p-tolylstannonate 2.0

Example 6 I Percent Mid-Continent mixed base SAE 50 98.4 Aluminum naphthenate 1.3

Example 3 Per cent Pennsylvania paraff n base SAE 10 99.40 Diethylthallium trichloroacetate 0.05

Naphthalene-chlorwax c o n d e n s a ti o n Tribenzyltin 3-isopropy1-6 methyl-3, 6-endoethylene-M-tet-rahydrophthalate 0.3

Example 7 Percent Mid-Continent paraffin base SAE 40 93.8 Volatilized corn oil 5.0 Chlorodiphenylene oxide 1.0 Trilauryltin phenylstearate 0.2

Example 8 Percent Naphthenic base SAE 30 98.0 Diphenyllead dichlorostearate 1.3 Methyl dichlorostearate 0.7

Example 9 Percent Castor oil 98.3 Sulfurized soy bean oil 0.2 Dicyclohexylarsenic oleate 1.0 Chlorodiphenyl 0.5

Example 10 In making a grease containing my 'addends I may use:

Percent Oleic acid 8.1 Lime 1.2 Water 0.3 Dichlorostearic acid 1.1 Bright stock 13.1

Distillate (440 seconds at FT) 70.0 Diamyltin divalerate 0.2

Example 11 In making a lubricating gasoline, I blend 0.5 per cent of the product of Example 1 with gaso- 2,288,288 I 9 It will be understood that certain features and stood that my invention is not to be limited to sub-combinations may be employed without refthe details described.

erence to other species or combinations. This Having thus described my invention, I claim: is contemplated by and is within the scope 01' A lubricant comprising in combination amajor my claim. It is further obvious that various 5 proportion of an oil of lubricating viscosity and changes may be made in details within the scope a minor proportion of diethylarsenic phenylof my claim without departing from the spirit stearate.

of my invention. It is therefore to be under- BERT H. LINCOLN. 

